python - 类型错误 : 'dict_keys' object does not support indexing

Question

def shuffle(self, x, random=None, int=int):
    """x, random=random.random -> shuffle list x in place; return None.

    Optional arg random is a 0-argument function returning a random
    float in [0.0, 1.0); by default, the standard random.random.
    """

    randbelow = self._randbelow
    for i in reversed(range(1, len(x))):
        # pick an element in x[:i+1] with which to exchange x[i]
        j = randbelow(i+1) if random is None else int(random() * (i+1))
        x[i], x[j] = x[j], x[i]

当我运行 shuffle 函数时，它会引发以下错误，这是为什么呢？

TypeError: 'dict_keys' object does not support indexing

Answer 1

很明显，您正在传递 d.keys()给您的shuffle功能。可能这是用 python2.x 编写的(当 d.keys() 返回一个列表时)。使用 python3.x，d.keys()返回 dict_keys行为更像 set 的对象比 list .因此，它无法被索引。

解决办法是通过list(d.keys()) (或简单地说 list(d) )到 shuffle .